The present invention relates to a storage device managing technique to manage operation of a storage device.
The amount of data to be handled by computers is rapidly increasing. To efficiently process such a large amount of data under the above condition, there has been broadly installed a storage connecting method (to be referred to as a storage network configuration hereinbelow) to configure storage networks such as a storage area network (SAN) and a network attached storage (NAS).
The storage area network has a configuration which supplies storage areas (to be referred to as volumes hereinbelow) of a storage device having a large amount of data storage areas to host computers (to be referred to as hosts hereinbelow). The volumes are supplied in block images.
In an ordinary case, the storage area network does not include a common or shared access control function. When two or more hosts access a volume in a shared way, volume access control is required between the hosts. Depending on the network configurations used in such storage area networks, the storage area networks are classified into fiber channel (FC) storage area networks (FC-SAN) and internet protocol (IP) storage area networks (IP-SAN).
In a typical configuration of the FC-SAN, a host bus adapter (HBA) of a host is connected to a port of a storage via a fiber channel switch and and/or a fiber channel hub using a fiber channel cable such as an optical fiber.
A typical configuration of the IP-SAN is implemented on ethernet (including such components as an ether cable, an IP hub, and an IP router)connected to a network interface card (NIC) of a host.
The network attached system has a storage network configuration which supplies a file system under shared access control is supplied via a network to hosts. Using protocols such as a network file system (NFS) and a common internet file system (CIFS), the network attached system can communicate data in a file image with the hosts.
A storage network configuration called “NAS over SAN” includes advantageous features of NAS and SAN. In the configuration, the hosts access files under shared control as in the network attached system. However, the data access method differs therebetween. The NAS over SAN uses shared access control to access meta-data (including a file name, a file size, and hierarchical structure information items of a file system) as in the network attached system. Data blocks are generally transferred via a high-speed path of FC-SAN. In the description below, “NAS over SAN” will be referred to as “NAS+SAN”.
In a storage allocation method using the storage area network, storage areas of a system in which storage devices are connected to servers by the storage area network are allocated to users according to requests from the users (reference is to be made to USP Application NO. 2002/0099914).